Nov 11 (Reuters) - Only two days left to this year’s U.N. climate negotiations in Glasgow – officially. Behind the scenes, some delegates worry the COP26 talks could go overtime into Saturday. But spirits were buoyed on Wednesday night by an unexpected joint statement by China and the U.S. pledging climate cooperation in tackling both methane emissions and deforestation.But earlier in the day, a first draft of a so-called Glasgow agreement had still left much of the hard work undone. That text would ask countries to upgrade their emissions-cutting pledges by 2022, and “urged” them to scale up climate finance while telling them to phase out coal use and subsidies for other fossil fuels. Climate-vulnerable nations said they would press for a stronger deal on financial aid, and some oil producing countries could baulk at the mention of fossil fuels. Saudi Arabia has said the climate deal should not swear off oil and gas.And once again the conclusions from the annual climate talks look set to dodge the details on how - and how much - rich nations should compensate for climate-linked losses and damages incurred by poor nations, which have contributed little to the problem. Meanwhile, talks on the side to resolve the so-called Article 6 rules to govern government-run carbon markets were ongoing. There is pressure by some forested countries as well as private investors to resolve the rules, which would likely then also inform standards for voluntary carbon markets. On Thursday, on-stage panelists and speakers were set to focus on urban issues – specifically, how to make sure that the world’s cities, towns and infrastructure are bringing down emissions and preparing for extreme weather in a warmer world. Denmark and Costa Rica will also officially launch their “Beyond Oil & Gas Alliance” and announce new members who will commit to stop handing out new oil and gas extraction permits and eventually halt domestic production. Britain, an oil producer, has opted out of that club. But behind the scenes, negotiations will be heating up on Thursday as a second draft of the deal is released and delegations dig in on their demands